In the game of roulette, the dealer, by hand, spins the rotatable central portion of the roulette wheel, known as the wheel head, in one direction while spinning the roulette ball, again by hand, in the opposite direction on the track formed around the periphery of the downwardly sloping bowl. As the speed of the ball diminishes, it rolls down the sloping bowl and enters one of a series of numbered compartments formed along the periphery of the wheel head, the compartments being alternately colored black and red.
The object of the game is for the players to guess the number of which compartment the ball will enter, or which color it will land on, or even chosing a group of numbered compartments, any of which if entered by the ball is considered a correct guess.
One of the problems encountered in the game of roulette is the fact that the dealer can, to a certain extent, control which compartment or at least which group of compartments or color the ball will enter, by adjusting the speed and the moment of release of the ball relative to the spinning wheel head, so that the possibility of collusion between the dealer and a player can exist.